jQuery.base64 = ( function( $ ) {

    var _PADCHAR = "=",
        _ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
        _VERSION = "1.1";//Mr. Ruan fix to 1.1 to support asian char(utf8)


    function _getbyte64( s, i ) {
        // This is oddly fast, except on Chrome/V8.
        // Minimal or no improvement in performance by using a
        // object with properties mapping chars to value (eg. 'A': 0)

        var idx = _ALPHA.indexOf( s.charAt( i ) );

        if ( idx === -1 ) {
            throw "Cannot decode base64";
        }

        return idx;
    }

    function _decode_chars(y, x){
        while(y.length > 0){
            var ch = y[0];
            if(ch < 0x80) {
                y.shift();
                x.push(String.fromCharCode(ch));
            }else if((ch & 0x80) == 0xc0){
                if(y.length < 2) break;
                ch = y.shift();
                var ch1 = y.shift();
                x.push(String.fromCharCode( ((ch & 0x1f) << 6) + (ch1 & 0x3f)));
            }else{
                if(y.length < 3) break;
                ch = y.shift();
                var ch1 = y.shift();
                var ch2 = y.shift();
                x.push(String.fromCharCode(((ch & 0x0f) << 12) + ((ch1 & 0x3f) << 6) + (ch2 & 0x3f)));
            }
        }
    }

    function _decode( s ) {
        var pads = 0,
            i,
            b10,
            imax = s.length,
            x = [],
            y = [];

        s = String( s );

        if ( imax === 0 ) {
            return s;
        }

        if ( imax % 4 !== 0 ) {
            throw "Cannot decode base64";
        }

        if ( s.charAt( imax - 1 ) === _PADCHAR ) {
            pads = 1;

            if ( s.charAt( imax - 2 ) === _PADCHAR ) {
                pads = 2;
            }

            // either way, we want to ignore this last block
            imax -= 4;
        }

        for ( i = 0; i < imax; i += 4 ) {
            var ch1 = _getbyte64( s, i );
            var ch2 = _getbyte64( s, i + 1);
            var ch3 = _getbyte64( s, i + 2);
            var ch4 = _getbyte64( s, i + 3);

            b10 = ( _getbyte64( s, i ) << 18 ) | ( _getbyte64( s, i + 1 ) << 12 ) | ( _getbyte64( s, i + 2 ) << 6 ) | _getbyte64( s, i + 3 );
            y.push(b10 >> 16);
            y.push((b10 >> 8) & 0xff);
            y.push(b10 & 0xff);
            _decode_chars(y, x);
        }
        switch ( pads ) {
            case 1:
                b10 = ( _getbyte64( s, i ) << 18 ) | ( _getbyte64( s, i + 1 ) << 12 ) | ( _getbyte64( s, i + 2 ) << 6 );
                y.push(b10 >> 16);
                y.push((b10 >> 8) & 0xff);
                break;

            case 2:
                b10 = ( _getbyte64( s, i ) << 18) | ( _getbyte64( s, i + 1 ) << 12 );
                y.push(b10 >> 16);
                break;
        }
        _decode_chars(y, x);
        if(y.length > 0) throw "Cannot decode base64";
        return x.join( "" );
    }


    function _get_chars(ch, y){
        if(ch < 0x80) y.push(ch);
        else if(ch < 0x800){
            y.push(0xc0 + ((ch >> 6) & 0x1f));
            y.push(0x80 + (ch & 0x3f));
        }else{
            y.push(0xe0 + ((ch >> 12) & 0xf));
            y.push(0x80 + ((ch >> 6) & 0x3f));
            y.push(0x80 + (ch & 0x3f));
        }
    }



    function _encode( s ) {
        if ( arguments.length !== 1 ) {
            throw "SyntaxError: exactly one argument required";
        }

        s = String( s );
        if ( s.length === 0 ) {
            return s;
        }

        //s = _encode_utf8(s);
        var i,
            b10,
            y = [],
            x = [],
            len = s.length;
        i = 0;
        while(i < len){
            _get_chars(s.charCodeAt(i), y);
            while(y.length >= 3){
                var ch1 = y.shift();
                var ch2 = y.shift();
                var ch3 = y.shift();
                b10 = ( ch1 << 16 ) | ( ch2 << 8 ) | ch3;
                x.push( _ALPHA.charAt( b10 >> 18 ) );
                x.push( _ALPHA.charAt( ( b10 >> 12 ) & 0x3F ) );
                x.push( _ALPHA.charAt( ( b10 >> 6 ) & 0x3f ) );
                x.push( _ALPHA.charAt( b10 & 0x3f ) );
            }
            i++;
        }


        switch ( y.length ) {
            case 1:
                var ch = y.shift();
                b10 = ch << 16;
                x.push( _ALPHA.charAt( b10 >> 18 ) + _ALPHA.charAt( ( b10 >> 12 ) & 0x3F ) + _PADCHAR + _PADCHAR );
                break;

            case 2:
                var ch1 = y.shift();
                var ch2 = y.shift();
                b10 = ( ch1 << 16 ) | ( ch2 << 8 );
                x.push( _ALPHA.charAt( b10 >> 18 ) + _ALPHA.charAt( ( b10 >> 12 ) & 0x3F ) + _ALPHA.charAt( ( b10 >> 6 ) & 0x3f ) + _PADCHAR );
                break;
        }

        return x.join( "" );
    }


    return {
        decode: _decode,
        encode: _encode,
        VERSION: _VERSION
    };

}( jQuery ) );